About 1.7 million years ago, a leggy human ancestor, Homo erectus, began prowling the steamy swamps and uplands of Java. That much is known from the bones of more than 100 individuals dug up on the Indonesian island since 1891. But the culture of early "Java Man" has been a mystery: No artifacts older than 1 million years had been found--until now. At the meeting, archaeologist Harry Widianto of the National Research Centre of Archaeology in Yogyakarta, Indonesia, wowed colleagues with slides showing stone tools found in sediments that he says were laid down 1.2 million years ago and could be as old as 1.6 million years. The find, at a famous hominid site called Sangiran in the Solo Basin of Central Java, "opens up a whole new window into the lifeways of Java Man," says paleoanthropologist Russell L. Ciochon of the University of Iowa in Iowa City.

Although hominids apparently evolved in Africa, Indonesia is a Garden of Eden in its own right, with a wealth of H. erectus fossils. The startling discovery 2 years ago of "hobbits"--the diminutive H. floresiensis of Flores Island--added a controversial new hominid to the Indonesian menagerie.

In 1998, Widianto found stone flakes in the 800,000-year-old Grenzbank layer at Sangiran, whose well-plumbed sediments reach back 2 million years. Then in September 2004, his team struck gold in a layer dated by extrapolation from the rocks around it to 1.2 million years ago. Over 2 months, they unearthed 220 flakes--several centimeters long, primarily made of chalcedony, and ranging in color from beige to blood red--in a 3-by-3-meter section of sand deposited by an ancient river.

The find, not yet published, could be even more spectacular than Widianto realizes, says Ciochon. His team, which also works at Sangiran, has used ultraprecise argon-argon radiometric methods to date the volcanic strata overlying the levels excavated by Widianto to 1.58 million to 1.51 million years ago--making the flakes at least 1.6 million years old. If the flakes were undisturbed, Ciochon says, they would represent "some of the earliest evidence of the human manufacture of stone artifacts outside of Africa." Their antiquity would match that of the oldest flakes found in China, at Majuangou, dated to 1.66 million years ago and also made of chert.

But not everyone is convinced. Although the chert flakes are abraded, possibly by water, a few limestone flakes are remarkably sharp. "The difference in preservation condition could indicate that we are dealing with secondary deposition," or flakes of different ages mixed together, cautions archaeologist Susan Keates of Oxford University in the U.K., who was at the talk. Others disagree. "I feel their excavation is reliable, because the deposits are thick and undisturbed," says Hisao Baba, curator of anthropology at Japan's National Science Museum and the University of Tokyo, whose team has also uncovered H. erectus fossils and flakes on Java.

The Sangiran flakes "are fundamentally different"--smaller--than the stone choppers made by H. erectus in Africa, says Ciochon. The evidence, he argues, suggests that Java Man had to range far for small deposits of good flint or chert and so created small, finely worked tools in contrast to the larger tools found in Africa. Considering the scarcity of raw materials on Java, Ciochon says, it's "a remarkably fine technology."

Widianto will resume excavations in June. "I will be going deeper and deeper, older and older," he promises.

Amazing to think humans have been around for well over a million years and this is how far we have come.

While this may be the earliest finding of H. erectus tools, other ancestors of ours were using simple Olduwan-style tools as far back as 2.4 million years ago. But it wasn't until 50,000 years ago or so that we really had the explosion in technology, art, etc. that allowed humans to take over the world. What's amazing isn't that that explosion didn't happen earlier, but that it happened at all.

Contemporaneous with the second migration out of Africa (that displaced or merged with, depending on who you believe, existing hominin populations), Homo sapiens began using new and far more complex tool technologies 40-50,000 years ago, began using art and burying their dead, began building living structures, and were living in larger and more complex societies. It was a radical transformation that took place in a fairly short period of time and completely changed the way hominins lived and behaved.

Amazing to think that people don't recognize our ability for rapid development as evidence *against* a 'million year' history for humanity.

Why? You're confusing cognitive and morphological evolution.

Yes, it would be amazing and we should have colonies in space by now... if we had really been around for a million years.

Maybe, if anatomically modern humans had been around for one million years, but we haven't been. I also think you more than slightly discount the costs associated with the earliest paleolothic tool technologies -- the jump from no tools to the simplest stone tools to more complicated, designed stone tools represents a much greater cognitive shift than the jump from chariots to corvettes.

I'm not sure there was a "cause," per se, but evidently a population stumbled on a winning formula that made them and their descendents much more fit than other hominin populations. Think of it as analogous to the discovery of iron, 3000 years ago: populations that had iron in a very short time were able to overrun every population in Eurasia that didn't have iron.

Another part of it is a population question -- these more advanced hunter/gather societies were able to support far larger populations that essentialy swamped what had been there before.

There is documented, gradual evolution in tool technologies leading up to this explosion, but if you're asking what the key turning point was, I don't know.

Look at it this way, If I were to ask you to produce for me a very simple "dinner fork" made of metal. But today's technology didn't exist. How long would it take you to first comprehend (design) it ie: probably not very long, Then find the metal to make it with, then actually "mine" the metal. Then how long will it take you to find a way to produce a fire hot enough to melt it down into useable ingots ie:roughly 2,000 degrees should suffice. Then you would need to design and build a machine of some sort to actually manufacture it. But then you need a way to power your machine preferably not by chaining a horse or donkey up to it. How long would it take you to acomplish such a feat ?, my guess is that one entire lifetime wouldn't be enough.

> But it wasn't until 50,000 years ago or so that we really had the explosion in technology, art, etc. that allowed humans to take over the world. What's amazing isn't that that explosion didn't happen earlier, but that it happened at all.

Three cheers for the Toba supervolcano and the near-extinction of the early humans as a result! Those who survived had to be the smarter and cleverer ones. Once the "jocks" got weeded out, the early "nerds" were able to lead humanity on it's road to the stars.

38
posted on 04/21/2006 12:12:26 PM PDT
by orionblamblam
(I'm interested in science and preventing its corruption, so here I am.)

There was some earlier debate in the paleoanthropological community as to the number of early human species in southern Africa between 3 and 1 million years ago. Conventional wisdom had it that two species existed, Australopithecus africanus and Paranthropus robustus. In contradiction to this view, Milford Wolpoff, of the University of Michigan, advocated the"single species hypothesis". It claimed that the differences between the southern forms were caused by age differences and sexual dimorphism of the specimens. Many researchers had problems with this hypothesis. For example, why in southern Africa were the supposed males dying at a different place than the supposed females? And why were they dated to almost a half a million years later? It was clear that a larger fossil record would be needed to prove or disprove this hypothesis.

Interestingly, the answer to the question of the southern African early humans would come from hundreds of kilometers away in East Africa. The discovery of two fossils, KNM ER 406 and KNM ER 732, at Koobi Fora in eastern Africa would provide the necessary expansion of the record needed to disprove the "single species hypothesis". Upon discovery its in 1969, ER 406 showed enough similar morphology to be assigned to the same species as OH 5; with the addition of ER 732, comparisons could be drawn between the two that could shed light on the nature of dimorphism in early humans. As these two specimens were examined, researchers found that the early humans of this period followed what is called the great ape model of sexual dimorphism. Male crania were larger than females, and more heavily constructed. While differences existed between the two skulls, these differences were exactly what would be expected between the sexes in other great apes.

The two southern African forms, however, did not fit this model of the distinction between the sexes. The differences were too great to be the result of sexual dimorphism. This observation favored the idea of two distinct species in southern Africa.

The final blow to the "single species hypothesis" was the 1975 discovery of the cranium KNM ER 3733, assigned now to Homo ergaster, in the same layer as ER 406, the "robust" form Paranthropus boisei. Scientists finally knew for sure that more than one species of early human coexisted in the same geographical area. The old single line of progressive evolution was, once and for all, split into branches. And the human family tree has never looked the same since.

The "Peninj mandible" is a nearly complete mandible of Paranthropus boisei. It provided researchers with their first understanding of the complete adult dentition and the structure of the lower jaw of this species.

I never heard that before. So I guess humans have considered other humans as different species when it fit their purpose. I thought if they could reproduce, they were the same species. Didn't Thomas Jefferson prove we are all one species?

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